Stereolithography Using Positive Direct-Mask Exposure

Abstract

This paper proposes a new stereolithography using liquid photo-initiator and base resin (photopolymer resin without photo-initiator) separately. First, base resin is supplied as a layer, and then a mask pattern is drawn onto the surface with photo-initiator using inkjet printing. When the surface is exposed with a UV lamp, only the drawn pattern is cured by the photo-initiator. In this process, the photo-initiator works as a positive mask and the uncured base resin can be used again because it is not mixed with the photo-initiator. The merits of this method are: (a) an area exposure instead of dot scanning enables fast fabrication, (b) no use of a mask device such as LCD or a laser leads to low cost, (c) keeping the base resin and photo-initiator separately leads to longer pot life of materials, (d) low viscosity and no curability of liquid photo-initiator itself enable more stability and liability of inkjet process, and (e) colored photo-initiator enables color fabrication. The basic idea, fabrication system implementation and the results of some fabrication experiments are presented.